The excitement around ADCs for treating cancer stems from the realization that traditional, small-molecule cytotoxic drugs and radiation are still some of the most potent anticancer agents, and that targeting them by tethering them to antibodies might bypass some of the side effects.

The biopharmaceutical industry currently has over two dozen ADC candidates estimated to be in its pipeline, indicating that there is a current demand for scientists with specific expertise in the techniques required for designing, synthesizing, and studying these molecules. In addition to developing expertise in-house, companies are frequently partnering with smaller companies or outsourcing projects to service providers to get the work done.

At Science Exchange, we have a unique bird’s-eye view of ADC-focused research and the service providers that are facilitating progress in this exciting field. Researchers who order services using the Science Exchange marketplace gain rapid access to an innovative network of 3,000+ service providers, including a number that supports ADC studies, through a single contract with Science Exchange. In this blog post, we’ll go through some of the key techniques and show how featured service providers in our network are meeting needs of ADC researchers.

Target discovery: the abundance challenge

Many ADC research programs seek to target cell surface proteins that are unique to the cell type that is to be killed by the cytotoxin. However, cell surface proteins, and other ADC targets, are usually low in abundance and underrepresented in traditional proteomic measurements.

One of the newest, cutting-edge providers on the Science Exchange network is Biognosys, offering discovery proteomics solutions based on Hyper Reaction Monitoring (HRM-MS™), a Next Generation proteomics technology. Invented at Biognosys, HRM-MS delivers quantification of up to 9’000 proteins per sample across treatments or conditions and identifies significantly regulated proteins. This platform is ideal for ADC target discovery studies, with one proof-of-concept study showing the quantification of over 500 cell surface proteins from matched biopsy samples.

The conjugation challenge

The ideal linker between the antibody and the cytotoxin drug is stable in the bloodstream, and if needed, can be cleaved in the specific environment of the target. Some ADC linkers are designed to dissolve the the reducing environment of the cytosol, while others require specific enzymes of certain subcellular compartments. Other linkers are non-cleavable. The linker also has to have minimal toxicity.

In addition to some wizardry in chemical synthesis, ADC development therefore requires experience in cell-based assays and drug metabolism studies. WuXi Apptec, MabPlex, and ChemPartner are service providers listed on the Science Exchange marketplace that have worked side by side with ADC developers on all aspects of linker synthesis and characterization.

85% of the surveyed researchers reported using LC-MS for ADC bioanalysis. However, over 24% respondents had to adapt traditional LC-MS methods, using affinity capture LC-MS or accelerator MS. 42% of respondents reported using ligand-binding assays, illustrating that most researchers use more than one technique in analyzing ADCs. The complexity of analytes, in combination with the lack of regulatory guidance around ADC analysis, have resulted in the need to use multiple, individually developed, methods.

Fortunately, the Science Exchange marketplace features the services of Biognosys, Anaquant, and ChemPartner, all of which provide experience in developing analytical methods for ADCs.

To address the challenge of quantifying multiple species per sample, Biognosys provides targeted proteomics services using Multiple and Parallel Reaction Monitoring (MRM and PRM), which are techniques that offer highly specific and sensitive multiplexed quantification of selected proteins from complex biological samples. These techniques deliver absolute or relative quantification of up to 150 target proteins per run with a dynamic range of 6 orders of magnitude.

Countless other service providers, such as Bio-Synthesis, Bionova, and Maine Biotechnology Services, are experts in analyzing ADCs using ligand-binding assays. In addition, Science Exchange’s in-house regulatory compliance team has expertise in working with representatives from regulatory agencies, to ensure that the analytical services carried out by our service providers meet necessary requirements.
ADC bioanalysis services on the Science Exchange marketplace include:

DAR (drug:antibody ratio) determination

Residual free drug analysis

Pharmacokinetics (PK) determination

Process development for ADC

Again, the heterogeneity of a batch of ADC can make it challenging to develop a scalable, reproducible, and robust manufacturing process. Manufacturing the antibody component of the ADC faces all the same challenges as does traditional therapeutic mAb production.

Given the demands of manufacturing, engineering quality by design is important in the nonclinical, preclinical and early clinical phases of ADC research. Expertise in antibody optimization, protein purification, and chemical synthesis are required to create less heterogeneous batches of antibodies, linkers, cytotoxins and conjugates.

Chandreyee Das

Senior Content Manager

Chandreyee Das, Ph.D. (Chemical Biology, UCSF) is Director of Marketing at Science Exchange with 15 years of research experience and 13 years of life science content marketing experience. Chandreyee was a Fulbright Scholar and won fellowships from the U.S. NSF and NIH. Following postdoctoral research at Dana-Farber Cancer Institute, she worked at MilliporeSigma, delivering scientific content to life science tools customers. She has published in both peer-reviewed and industry news outlets.